Method for the automated generation of technical assembly instructions from a digital model

Abstract

A method and a device for the automated generation of technical assembly instructions from a digital model, in particular a CAD model, of an assembled object. The technical assembly instructions are generated by disassembling the components of the digital model step by step in reverse order.

Description

Method for the automated generation of technical assembly instructions from a digital model

[0001] The invention relates to a method and a device as well as a computer-readable medium for the automated generation of technical assembly instructions from a digital model of an assembled object, in particular a CAD model.

[0002] Technical assembly instructions are an essential component of manufacturing and assembly processes in a wide variety of industries. Although CAD software already offers the ability to create three-dimensional models and display them in great detail, generating comprehensive technical assembly instructions has so far required a significant amount of manual effort. The main problem is that every single movement, every assembly step, and every tool must be manually inserted into the instructions. These must be logically linked. This process is time-consuming and error-prone.

[0003] The object of the invention is to provide an automated method for generating technical assembly instructions from a digital model of the object to be assembled.

[0004] This object is achieved according to the invention by the features of claims 1, 14 and 15.

[0005] The invention relates to a method for the automated generation of technical assembly instructions from a digital model of an assembled object, in particular a CAD model, wherein the digital model has at least two components. The method according to the invention is characterized by the following method steps: a. Step-by-step disassembly of the components of the digital model b. Creation of the technical assembly instructions based on the step-by-step disassembly in reverse order.

[0006] The invention is based on a real object that requires assembly. Such real objects can, for example, relate to furniture, toys, electrical appliances, cars, heating systems, water systems, electrical systems, as well as components or assemblies of these objects.

[0007] The actual object according to the invention is available in the assembled state as a digital model. Such a digital model can, for example, be used in a CAD format, in a neutral exchange format such as STEP, STP, JT or Obj.

[0008] The digital model according to the invention must contain two or more components, the assembly of which is to be shown in technical assembly instructions.

[0009] The technical assembly instructions are created by gradually disassembling the components of the digital model in reverse order. In other words, the method according to the invention starts with the assembled digital model and ends with a subset of components that the method disassembles last. The assembly instructions start from the subset of components and proceed step by step through the disassembly process backwards, ending with the fully assembled digital model. This process is also called "assembly by disassembly."

[0010] In an optional step, preferred components are identified in the digital model. For this purpose, the tree group structure of the digital model can be considered, for example. Together with an algorithm not according to the invention or a K1 algorithm, individual components are isolated from the digital model.

[0011] In a further optional step, primitive contact features between components are determined. This can be done by determining contact features between all components, a subset of components, or components that are touching or at a certain distance from each other.

[0012] A primitive contact feature is a contact between two or more components that are very close to each other or not at all. This distance can be in the single-digit micrometer range, for example, -1 pm, 0 pm, or +1 pm. The type of contact is also determined in the primitive contact feature. Contact types can be: planar contacts (two surfaces touching), cylindrical contacts (one cylindrical surface touching another cylindrical surface, such as a shaft in a bearing), point contacts, torus contacts, spline contacts (e.g., the thread of a screw), or conical contacts. It is also checked whether bodies overlap, so-called "fixing contacts." Such contacts could be, for example, a retaining ring. In the relaxed state, this has a smaller inner diameter than the component to which it is attached.

[0013] In a further step, a matrix is ​​preferably created that Contains a plurality of components, with all components to be described in the matrix being represented on the x- and y-axes of the matrix, with the matrix entries describing the type of primitive contact feature present. A matrix according to the invention could look as shown in Table 1.

[0014] Table 1 shows a matrix according to the invention. Bl-Bn are components of the digital model according to the invention. The entries in the matrix are based on the primitive contact features. The different numbers in the matrix indicate the type of contact between the components. For example, " defines that it is the same component. Entry 2 could, for example, be a conical contact, 3 a planar contact, etc. A component could also have several Contact types are also represented in the matrix. This can either continue to be done with a single number. For example, 5 could represent planar and cylindrical contact, or with a series of numbers that enumerates all contact types, e.g., [2, 3]. Additional information about the contact type can be stored in an optional database. Bl B2 B3 ... Bn Bl - 2 0 x 3 B2 2 - 4 x 0 B3 0 4 - x 0 ... xxx - 0 Bn 3 0 0 0 - Table 1 : Matrix representation of the primitive contact features

[0015] Based on this matrix and / or some of the primitive contact features, higher-level contact features are preferably determined. For higher-level contact features, for example, a check is made to determine whether a cylindrical contact has a through-hole, a countersunk through-hole, or a blind hole. This combination of contact features is used to identify no, one, or multiple free removal directions for a component. In other words, higher-level contact features are determined for certain primitive contact features that limit the free removal directions of the component to be removed based on the geometric properties of at least one of the components.

[0016] The free expansion directions of a component can be a maximum of 6 or 12 The free expansion directions can be achieved by three translational and three rotational degrees of freedom, each allowing movement in two directions.

[0017] In an optional embodiment, the free removal directions of the component to be removed are specified in the coordinate system of the component to be removed of the component pair or in the coordinate system of the component pair.

[0018] A component pair corresponds to the components to be separated from each other.

[0019] In an optional embodiment of the invention, a check is carried out to determine whether another component is in the path along the free removal direction, with which the component to be removed could collide. In other words, the free removal direction is a direction in which the at least one found component can be separated from the assembled model without colliding with another component.

[0020] In a further optional embodiment of the invention, a check is carried out to determine whether another component is in the path along the free removal direction, which is neither the component itself nor the component from which it was originally separated, with which the component to be removed could collide. In other words, a check is carried out for collision with another component, which also includes checking for collision with an additional component that is not one of the components to be separated.

[0021] In an optional embodiment, the collision analysis is carried out using a projection of the component to be removed.

[0022] In an optional embodiment, only removal directions between components that touch each other are determined.

[0023] In an optional embodiment, all expansion directions between all components are determined.

[0024] The above steps can be performed iteratively for each assembly step, whereby the digital model can be analyzed for currently dismantled components, while already dismantled components can be ignored.

[0025] Demountable components are, for example, components that have at least one free removal direction.

[0026] In an optional embodiment of the invention, at each step-by-step disassembly step, at least one component is searched for in which at least one free expansion direction exists.

[0027] The determination of the free expansion directions and collisions results in assembly information that can be transferred to an editor.

[0028] Assembly information can contain all assembly steps, a subset of assembly steps, or a single assembly step. For example, the assembly information can contain all or a subset of the free assembly directions, as well as the component pair(s) to be separated for the corresponding assembly step, all assembly steps, all components, or a subset of all components in the digital model.

[0029] The assembly information is used to create a graphical representation of at least one disassembly or assembly step for a user. A graphical representation can, for example, be a document in .doc, .docx, .pdf, .xml, .html, or an equivalent format. A graphical representation in the form of a 2D or 3D editor file, which stores the corresponding assembly sequences including the animations, is also preferred. This 2D or 3D editor file can, for example, be stored in a .gib, .gltf, or an equivalent format and optionally be provided with metadata, which is preferably stored in an included or separate .json file. A graphical representation as an image, for example in .tiff, .gif, .jpg, .png, or an equivalent format, or as a video, for example in .mp4, .avi, .mov, or an equivalent format, is also preferred.

[0030] In an optional embodiment of the invention, a direction-indicating element, in particular an arrow, is automatically inserted in the graphic representation opposite to the free removal direction of the components to be separated.

[0031] In an optional embodiment of the invention, it is analyzed whether a tool is required to separate the components to be separated. For example, it could be detected that one of the components to be separated is a screw.

[0032] In an optional embodiment of the invention, a suitable tool for separating the two components to be separated is displayed in the graphic representation. For example, a screwdriver could be displayed in conjunction with a screw. Additionally, the appropriate type of screwdriver, such as Phillips, slotted, pentalobe, etc., could also be displayed.

[0033] In an optional embodiment of the invention, all or a subset of the components to be installed in this assembly are shown in the graphical representation. Step displayed in a parts list.

[0034] In an optional embodiment of the invention, the components to be installed are specified to scale or in a specified scale, for example in the parts list.

[0035] In the following, preferred embodiments of the invention are explained with reference to figures.

[0036] They show: Fig. 1 ad a preferred embodiment of the technical assembly instructions for a shelf according to the invention Fig. 2 a sectional side view of a countersunk hole and its contact surfaces Fig. 3 a simple example of a screw connection of 2 plates

[0037] Fig. 1a - Fig. 1d show a preferred embodiment of assembly instructions created according to the invention. This example shows how an assembly could be presented iteratively, step by step.

[0038] Fig. 1a shows the fully assembled digital model 4 in this exemplary embodiment. Individual components may be colored differently in this representation (represented here by different hatching). Component 10, which is also depicted in the following figures, is highlighted, for example.

[0039] In this preferred embodiment, Fig. 1 b shows a representation of a possible first assembly step, which represents the assembly information of the first assembly step. The optional parts list 5 indicates the components required for the corresponding step. The optional step counter 6 indicates the corresponding assembly step. The left-hand state 7 could display the initial state of the last assembly step, including the new components to be assembled. The right-hand state 8 could display the assembled state of the components to be assembled in this assembly step. In this example, only one component—component 10—is assembled, as it is the first assembly step.

[0040] Fig. 1c shows a possible second assembly step in this preferred embodiment. On the left side, pins 9 can be seen in the unassembled state. On the right side, pins 9 can be seen in the assembled state with component 10.

[0041] Fig. 1 d shows in this preferred embodiment the representation a possible final assembly step. On the left, component 12 can be seen in its unassembled state. On the right, component 12 can be seen in its assembled state. It is also noticeable that the image section has changed compared to the other assembly steps.

[0042] It should be noted that the method or device according to the invention for creating the assembly instructions creates Figs. 1a-1d in a different order. The order shown here corresponds to a preferred graphic representation.

[0043] However, the method or device according to the invention begins with the fully assembled digital model 4 in Figure 1a and then proceeds through the disassembly step by step. The first disassembly step therefore corresponds to the last assembly step shown in Figure 1d, followed by many further disassembly steps up to the last disassembly step, which is the first assembly step shown in Figure 1b.

[0044] Fig. 2 shows contact features between two components. This example shows a cylindrically countersunk bore in a component 13 with a screw 14. The two components each have two contact features between them. The dashed line indicates a planar contact that restricts the free removal direction in the -Y direction. In the +Y direction, the screw 14 would be removable. The dotted line indicates a cylindrical contact that restricts the free removal directions in the -X, +X, -Z, and +Z directions. By exclusion, this results in a free removal direction in the +Y direction for the screw 13 in the countersunk bore of component 14 in this example.

[0045] In a preferred embodiment of the invention, potential rotation directions are also determined based on the contact features of Fig. 2. For example, without considering the thread in the above example, the screw can be rotated in two directions around the Y-axis, but not around the X- or Z-axis, since the conical contact would prevent this rotation and the screw would collide with the other component.

[0046] A component pair corresponds to the components to be separated. In Fig. 3, for example, this would be plate 1 and screw 3, as well as plate 1 from plate 2 and plate 2 from screw 3.

[0047] Fig. 3 describes the disassembly of two plates using a screw with the components plate 1, plate 2 and screw 3.

[0048] First, the contact features between the components determined, e.g. planar contact between plate 1 and plate 2, cylindrical and planar contact between plate 1 and screw 3, and cylindrical contact between plate 2 and screw. Based on these contact features, for components 1-3, only -X for screw 3 would be possible as a disassembly direction due to the countersunk hole, and for plate 2 the direction would be +X. Likewise, component pair 3-2 would have the disassembly directions -X for the screw and +X for plate 2. For component pair 1-2, due to the planar contact, the disassembly directions -X, +Y and -Y would be possible for plate 1, and +X, -Y and +Y for plate 2.

[0049] In a preferred embodiment, possible free removal directions for a component are determined using a collision analysis by checking for collisions. In the example in Fig. 3, plate 1, for example, would be checked. For this, there are the removal directions +Y, -Y, +X (from component pair 1-2) and the removal directions +X (from component pair 1-3). Thus, during disassembly, plate 2 would collide with screw 3 in the -Y and +Y directions. This information on possible collisions is also taken into account when determining free removal directions.

Claims

Claims 1. A method for the automated generation of technical assembly instructions from a digital model of the assembled object, in particular a CAD model, wherein the digital model has at least two components, characterized by the following method steps: - Step-by-step disassembly of the components of the digital model - Preparation of the technical assembly instructions based on the step-by-step disassembly in reverse order.

2. Method according to claim 1, wherein in each step-by-step disassembly step, a search is made for at least one component for which at least one free removal direction exists.

3. The method according to claim 2, wherein the free removal direction is a direction in which the at least one found component can be separated from the assembled model without colliding with another component.

4. The method according to any one of claims 1-3, wherein the step-by-step disassembly of the components of the digital model begins with the fully assembled model.

5. The method according to any one of claims 1-4, wherein the technical assembly instructions begin with a subset of the components of the fully assembled digital model.

6. Method according to claims 2-5, characterized by the step: determining whether two components touch, determining a primitive contact feature which describes the manner in which two components touch.

7. The method according to claim 6, characterized by the step: Creating a matrix that contains a large number of components, with all components to be described in the matrix being on the X and Y-axis of the matrix, where the entries of the matrix describe which type of primitive contact feature is present.

8. Method according to one of claims 6-7, wherein for certain primitive contact features higher-level contact features are determined, which further restrict the free removal directions of the component to be removed based on geometric properties of at least one of the components.

9. The method according to any one of claims 2-8, wherein at least none, one, or more free removal directions are determined based on at least three translational degrees of freedom, wherein the three translational degrees of freedom correspond to six potential removal directions, wherein free removal directions correspond to potential removal directions in which the component to be removed does not collide with any other component along the free removal direction, or wherein at least one free removal direction is determined based on at least three rotational degrees of freedom, wherein the three rotational degrees of freedom correspond to six potential rotational directions, wherein free removal directions correspond to potential rotational directions in which the component to be removed does not collide with any other component along the free removal direction.

10. Method according to one of claims 2-9, wherein the checking of the collision with another component also concerns the checking of the collision with an additional component which is not one of the components to be separated from one another.

11. Method according to one of claims 1-10, characterized by the following method step: a. Creating a graphic representation of at least one disassembly step or assembly step for a user.

12. Method according to one of claims 2-11, wherein contrary to the free A direction-indicating element, in particular an arrow, is automatically inserted in the direction of removal of the components to be separated.

13. Method according to one of claims 2-12, characterized in that only removal directions are determined between component pairs which touch each other, or that the digital model is analyzed for currently dismantled components, whereby components which have already been dismantled are disregarded or the free removal directions of the component to be removed are specified in the coordinate system of the component of the component pair to be removed or in the coordinate system of the component pair.

14. Device for carrying out the method according to one of claims 1-13, for the automated generation of technical assembly instructions from a digital model.

15. Computer-readable medium containing information for carrying out the method according to any one of claims 1-13 for automatically generating technical assembly instructions from a digital model.

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